The present invention relates to a fan assembly for cooling electronic devices, and more particularly, to a fan assembly that defines a smooth exterior surface to facilitate slidably engaging a receiving surface for mounting the fan assembly thereto.
Typical electronic devices, such as computers, incorporate internal cooling fans and blowers in order to maintain the temperatures of other internal components within specified design limits. The determination of optimal air flow requirements is based upon consideration of the thermal aspects of the layout of the device enclosure. The proper placement of an internal cooling fan in relation to the other internal components can significantly reduce the air flow rate required to achieve the desired cooling characteristics, and in turn reduce the associated power and noise characteristics by employing a smaller-sized fan. However, the close packaging of internal components to attain minimum package size often results in some obstruction to or deflection of the air stream in a location near the fan.
In order to achieve optimal performance, cooling fans are mounted onto an internal surface of the enclosure at a specified location. Generally, the means employed for mounting these cooling devices are limited by the relative ease of assembly and disassembly, the time required for assembly and disassembly, and the associated costs. Such fan assemblies typically include a fan housing secured to a mounting member. The configuration of the exterior surface of the mounting member opposite the surface to which the fan is mounted is of particular importance. For tube axial fans, it is frequently necessary that such fans be mounted flush to the receiving surfaces of the enclosures (referred to as xe2x80x9cflush face tube axial fan attachmentxe2x80x9d). Thus, in order to achieve this condition, it is necessary for the mounting member to define a smooth exterior surface.
It is known in the prior art that inserting a fastener from the exterior surface of a mounting member to secure a fan housing thereto will interrupt the exterior surface of the mounting member and prevent flush face tube axial fan attachment. For example, the heads of screws inserted through a mounting member to secure a fan housing thereto will interrupt the exterior surface of the mounting member and thereby prevent the fan assembly from mounting flush to the receiving surface of the enclosure. One known method for mounting a fan housing to a mounting member that overcomes this problem incorporates threaded standoffs attached to a sheet metal mounting panel. The threaded standoffs are press fit into the sheet metal mounting panel, and the free ends of the standoffs are received within the mounting apertures of the fan housing. Then, screws are inserted into the mounting apertures and threadedly engage the standoffs to fixedly secure the housing to the panel. Because the threaded standoffs are press fit into the sheet metal panel, the side of the panel opposite the fan housing maintains a smooth and flush surface to thereby allow flush face tube axial fan attachment. One of the drawbacks of this prior art approach, however, is that the threaded standoffs are relatively expensive and therefore involve increased manufacturing costs associated with purchasing and maintaining an inventory of such standoffs. Another drawback of this prior art approach is that it involves increased. production time for installing the threaded standoffs, particularly when multiple fan attachments are required.
Other known methods for mounting fan housings to mounting members or other sheet-like surfaces incorporate a variety of constructions generally comprising prefabricated, self-locking protuberances on a fan frame and extending through cooperative receptacles formed in the sheet-like surface. For example, U.S. Pat. No. 5,788,566 to McAnally et al. (xe2x80x9cthe ""566 patentxe2x80x9d) shows four prefabricated mounting hooks formed on respective corners of a fan housing and extending outwardly therefrom. Four corresponding slots are formed in the wall of a computer housing for receiving the mounting hooks. As further described in the ""566 patent, the fan housing is advanced towards the wall until the mounting hooks extend through the slots in the wall and are releasably locked therein.
Similarly, U.S. Pat. No. 5,677,829 to Clemens (xe2x80x9cthe ""829 patentxe2x80x9d) shows four prefabricated upstanding comer posts formed on respective comers of a mounting member for engaging corresponding slots in a fan housing. Each comer post is bifurcated so that it compresses as it is pushed into the corresponding slot. The opposite side of the mounting member includes downwardly projecting tabs for locking the fan assembly to a heat sink. Likewise, U.S. Pat. No. 5,707,282 to Clements et al. (xe2x80x9cthe ""282 patentxe2x80x9d) shows a method for mounting a fan housing to a mounting member in the form of a diffuser by employing a plurality of rearwardly extending posts prefabricated on the diffuser that engage corresponding apertures in the fan to restrain lateral movement of the fan relative to the diffuser. The ""282 patent further shows parallelepiped projections extending outwardly from the opposite side of the diffuser for mounting to a support.
One of the drawbacks associated with these prior art approaches is that they necessarily require the protuberances to extend through the mounting surfaces and thereby create an interrupted, uneven exterior surface opposite the mounted fan. As a result, these prior art assemblies cannot be used to achieve flush face tube axial fan attachment.
Accordingly, it is an object of the present invention to overcome one or more of the above-described and other drawbacks and disadvantages of the prior art.
The present invention is directed to a fan assembly for cooling electronic devices, and a method of making such a fan assembly. The fan assembly includes a fan housing defining a plurality of mounting apertures, and a mounting member for mounting the fan housing thereon. The mounting member is preferably in the form of a sheet metal panel, and includes a plurality of mounting tabs extending outwardly of the mounting member and received within the mounting apertures of the fan housing. An aperture is formed adjacent to each mounting tab and extends through the mounting member. Threaded fasteners are received within the mounting apertures of the fan housing, and engage both the mounting tabs and the fan housing to secure the fan housing to the mounting member.
The method of making the novel fan assembly includes piercing the mounting member in a predetermined shape, and moving the pierced metal outwardly of the mounting member to form each mounting tab. The fan housing is placed onto the mounting member, and the mounting tabs are received within the mounting apertures of the fan housing. To complete the assembly, fasteners, such as self-tapping screws, are inserted into the mounting apertures of the fan housing from the side opposite the mounting member. The fasteners engage both the fan housing and the mounting tabs to secure the fan housing to the mounting member.
One advantage of the present invention is that it eliminates the costs associated with purchasing and maintaining an inventory of extra parts associated with assembling the fan housing to the mounting member, such as threaded standoffs. In addition, the elimination of such extra parts reduces the time required to assemble the fan housing to the mounting member. Another advantage of the present invention is that the novel method of forming the mounting tabs out of the mounting member, and extending the mounting tabs into the corresponding mounting apertures of the fan housing, does not disrupt the smooth exterior surface of the mounting member opposite the fan housing. As a result, the fan assemblies of the present invention are particularly well suited for flush face tube axial fan attachment.
Other objects and advantages of the present invention will become apparent in view of the following detailed description of the preferred embodiments and accompanying drawings.